Apparatus for the production of bags from precut leaves with thermoplastic



April 16, 1963 A, EGLI APPARATUS FOR THE PRODUCTION OF BAGS FROM PRECUTLEAVES WITH THERMO-PLASTIC Filed Aug. 11, 1960 United States Patent OAPPARATUS FOR THE PRODUCTIGN OF BAGS FROM PRECUT LEAVES WITHTHERMOPLASTIC Alwin Egli, Neuhausen am Rheinfall, Switzerland, assignorto Schweizerische Industrie-Gesellschaft, Neuhausen am Rheinfall,Switzerland Filed Aug. 11, 1960, Ser. No. 48,944 Claims priority,application Switzerland Aug. 19, 1959 1 Claim. (Cl. 931-12) The presentinvention relates to the production of bags from pre-cut leaves providedwith thermoplastic material at least on the margins to be interweldedfor the formation of seams, by the formation of a tube or hose of the`said leaf, interwelding of a longitudinal seam thereof and subsequentfolding and interwelding of the bottoms of -said bags.

Hitherto all these operations have been carried out on one and the samemandrel, several such mandrels being combined into a mandrel wheel andbeing turned stepwise from one working position to the subsequent one,each of the said mandrels being provided with folding members andheating jaws for the formation of the tube or hose and of the seams.

It is an object of the present invention to provide a machine for theproduction of receptacles and bags of the kind referred to which has ahigh output while dispensing with a plurality of tube or hose formingand seam forming means.

With-these and other objects in view Which will become apparent laterfrom this specification and the accompanying drawing, I provide anapparatus for the production of bags from pre-cut leaves provided withthermoplastic material at least at the margins to be interwelded by aseam, comprising means for folding a Ileaf into a tube or hose andinterwelding a longitudinal seam thereof on a single auxiliary mandrel,moving the said auxiliary mandrel axially towards a main mandrel,transferring the said tube or hose axially from said auxiliary mandrelto the said main mandrel, and folding and interwelding the bottom ofsaid tube or hose on the end face of the said main mandrel.

I also provide a device for the production of such bags, comprising incombination: at least two main mandrels stepwise rotatable into variousworking position for the folding and interwelding of the bottoms of thesaid bags, and auxiliary mandrel 4ico-operating with the said mainmandrels and axially movable towards the main mandrel actually injuxtaposition with it, a folding box for the folding of the said leavesinto a tubular member and heatable clampingand welding-jaws for theformation of protruding longitudinal weld seams of the tube or hoseco-operating with the said auxiliary mandrel, and feeder rollersengaging the protruding longitudinal seam of the said tube or hose, andtransferring the latter from the said auxiliary mandrel to the saidactually juxtaposed main mandrel.

These and other features of my said invention will be clearly understoodfrom the following description of a preferred embodiment of my newdevice given by way of example with reference to the accompanyingdrawings, in which:

FIG. l illustrates a longitudinal section of the auxiliary mandrel and amain mandrel of a device for the production of bags,

FIG. 2 is a cross section on line II-II of FIG. l of the auxiliarymandrel with the folding box and the heating jaws in the workingposition in juxtaposition with the folding box,

FIG. 3 is a cross section like FIG. 2 in the Working position during thewelding of the longitudinal seam,

FIG. 4 is a diagrammatic illustration of the transfer of j 3,085,473Patented Apr. 16, 1963 the tube for the bag by pushing it from theauxiliary mandrel on to a main mandrel, and

FIG. 5 is a plan view to FIG. 4, FIGS. 4 and 5 being on a smaller scalethan FIGS. l to 3.

In FIG. 1 an auxiliary mandrel is denoted as at 1, which is axiallyslidably mounted on two bars 5. The bars `Slare fixed to an arm 6, whichis xedly connected to the machine frame. The axial shi-fting of theauxiliary mandrel 1 is effected in the working rhythm of the machine bythe rocking of a lever 7, which is connected by a connected rod 8 to theauxiliary mandrel 1. On an axle 9, likewise fixed to the machine frame,two rocker levers 10, 11 are pivoted, which at their lower ends carrytwo heating jaws 12, 13 serving for the welding of the longitudinalseam. The jaws 12, 13 are electrically heated in a well known andaccordingly not illustrated in detail.

Below the auxiliary mand-rel 1 a bi-partite folding box 14 is arranged,which is vertically shiftable from the position shown in FIG. 2 in fulllines into a position shown in chain-dotted lines. With its uppersurface it forms a table 16 with holders 18 serving for taking in apre-cut leaf 17, from which the bag is made. The folding box encloses apunch 15, likewise vertically shiftable, which cooperates with theunderside of the auxiliary mandrel 1 and forces the leaf 17 to be foldedagainst the same. On the axle 9 moreover a conveyer' roller 19 ispivotally mounted. The same co-operates with a similar roller 20 (FIG.5) and serves for transferring the tube or hose forl the bag f-rom theauxiliary mandrel 1 to the main mandrel 2. The rollers 19, 20 aredriven, in a manner not illustrated, from the principal drive of themachine, i.e. preferably continuously.

On a vertical axle 4 there is arranged a mandrel Wheel 3, having forexample four main mandrels 2, one of which is illustrated in section.The vertical shaft 4 is rotated in a step by step manner to successivelymove the main mandrels 2 into and out of the work station by a suitablemechanism 50 such as is shown in United States Patent 1,020,821 toHesser, issued March 19, 1912. The lowerwall 2l of the main mandrel 2 ispivotally mounted about a horizontal axle 22 capable of being swunginward against the bias of a coiled spring 23, in order to facilitatethe pushing over of the tube or hose for the bag. The inward pivoting ofthe bottom wall 21 takes place automatically, when the main mandrel 2runs into theworking position illustrated, opposite the auxiliarymandrel 1. In this position a roller 27 arranged on the bottom wall 21runs up a fixed abutment 28, whereby the bottom Wall 21 is turnedinward. Above the upper edge of the main mandrel 2 there is moreoverarranged a clamping jaw 24, which is mounted on a rocker arm 25co-operating with a lever 26 actuated by the .principal machine drive.

The method for producing the bags comprises the following steps:

A pre-cut leaf or blank 17 is supplied to the table 16, lbeing broughtinto the correct position by the holders 18. Thereafter the folding box14 with the punchy 15 move upward. The leaf or blank 17 is forcedagainst the bottom of the auxiliary mandrel 1 by the punch 15. Thefolding box 14 continues to move upward until the table 16 is flush withthe upper edges of the auxiliary mandrel 1 (chain-dotted line positionin FIG. 2). The leaf or blank 17 is thereby folded about the two sidefaces and the bottom portion of the auxiliary mandrel 1. By a rockingmovement of the rocker lever 10 the side 17 protruding upward from theleaf or blank 17 is folded by the jaw 12 of said lever about the upperface of the auxiliary mandrel 1. At the same time the lever 11 turnsinto the position shown in FIG. 3. The margins of the leaf 17 protrudingupwardly and provided'with a thermoplastic coating are then compressedby the heating jaws I2, 13 and thus interwelded. Thereafter the jaws 12and 13 release the protruding margin of the leaf 17, which has now beeninterwelded to form a hose. The lever 7 then shifts the auxiliarymandrel 1 to the right of FIG. 1, until its end face abuts the adjacentend face of the main mandrel 2. Thereby the forward end of theprotruding longitudinal seam of the tube or hose gets between the drivenrollers 19 and 20, is engaged by the same land the tube or hose ispushed over the main mandrel which had been in a position of readiness.In order to facilitate the pushing over the lower wall 21 of the latterhas been slightly turned upward (FIG. V4). With advantage `moreover themain mandrel is made slightly narrower than the auxiliary mandrel, whichlikewise contributes to the safe transfer from the auxiliary mandrel.Thereafter the lever 26 forces through the rocker arm 25 the clampingjaw 24 against the main mandrel 2, so that the tube or hose is retainedthere. The auxiliary mandrel 1 runs back again to its basic position,while the main mandrel 2 is turned about the axle 4 into a furtherworking position, where in a manner known in itself the folding andinterwelding of the lbottom of the bag is carried out. Previously theroller 19 has been swung out of its working position, in order to afforda free passage to the protruding seam `during the step-movement of themandrel wheel which is rotated stepwise according to United StatesPatent 1,020,821 to Hesser, issued March 19, 1912. The roller 19 couldnatur-ally be arranged axially adjustably instead of pivotally, for thepurpose of releasing at any time the longitudinal seam.

The use of an auxiliary mandrel 1 for the formation of the tube or hosefacilitates the formation of a seam, which is faultless over its fulllength. For this purpose the auxiliary mandrel is made longer than thetube or hose to be produced, while the mainy mandrel 2 -rnust be madeshorter than the latter, since one end of the tube or hose mustprojectbeyond the main mandrel in order that it can be folded for theformation of the bottom of the tube or hose to `form a bag.

While I have herein described and illustrated in the accompanyingdrawing what may be considered a typical and particularly usefulembodiment of my said invention, I wish it to be understood, that I idonot limit myself to the particular details and dimensions described orillus- 4 trated; for obvious modifications will occur to a personskilled in the art.

What I claim as my invention and desire to secure by Letters Patent, is:

In an apparatus for forming bags Ifrom precut blank sheets provided atleast Ialong the marginal edges with a thermoplastic material to beinterwelded and form a seam along one side of said bag, comprising stepby step support means, a work `station spaced from said support means, arotatable carrier on said support means, a plurality of radiallyextending main mandrel sections on said carrier movable stepwise intoand out of registry with said work station, expansible and retractablesections for each of said radial sections, slide guide means mounted atsaid work station extending in the same plane as said radially extendingmain mandrel section on said carrier, an auxiliary mandrel slidablymounted on said slide guide means adapted to be moved toward and away`from the end of each lmain mandrel section while said sections are intheir work `station position, means for moving said mandrel toward andaway from `said main mandrel sections as they are successively moved totheir work station position, a 4forming box beneath said auxiliarymandrel having a forming chamber over which one of said sheets isadapted to be placed and moved upwardly around said auxiliary mandrel, apair of jaw members mounted above said auxiliary mandrel to engage thefree ends of said sheet and move the same into sealing engagement toform a longitudinal upstanding seam, roller means located at said workstation to frictionally engage said seam when the auxiliary mandrel smoved to a position adjacent the end of one of said main mandrels, andmeans for retracting the expansible sections of said main mandrels whenthe same approach saidwork station to permit said roller means to feedthe formed blank'endwise over said main mandrel section.

References Cited in the lile of this patent UNITED STATES PATENTS2,671,383 Jungmayr Mar. 9, 1954 2,821,121 Vergobbi Jan. 28, 19582,854,899 Bauder et al. Oct. 7, 1958 2,966,832 Vergobbi Jan. 3, 1961

